This invention relates to the field of electronic musical instruments, in particular electric guitars and the like associated with electronic amplification, where a musician playing an instrument wishes to manipulate variations in the timbre of notes played. More particularly, this invention relates to a method of modifying the frequency response of a musical instrument amplification system by means of a sensor actuated by the musician playing the instrument, to provide the musician with expression control thorugh a continuously variable range of frequency response shapes including a condition of essentially flat frequency response.
It is well known to modify the electrical sound output from an electric guitar or the like by means of electronic circuits controlled by a foot pedal sensor. Such pedal sensors and related electronics circuits are referred to as "effects pedals". An effect pedal is customarily equipped with a foot operated switch, called a "bypass" switch for cancelling the modified sound when it is desired to revert to normal "dry" sound having a substantially flat frequency response for reproducing the original sound unmodified. The bypass switch is not intended to be operated during the performance of musical passages, since the switching is abrupt and musically disruptive. Consequently, such switching normally must be avoided by the musician during performance of a continuous musical passage.
The present invention originates from the discovery that the variety of expression available from an ordinary effect pedal could be extended and enhanced by including within the range of the pedal, the "dry" flat frequency response condition, and providing the ability to blend smoothly to the modified effect using the pedal, thereby eliminating the bypass switch as a separate entity, but retaining its function, not merely as an option to be selected between musical performances, but as a distinctively expressive element continuously variable during musical performance.